WinCreateMsgQueue

After calling WinInitialize, you must call this function if your thread needs to respond to messages. Save the handle, as other functions need it as input.

Syntax

WinCreateMsgQueue( hab, maxMsg ) : Creates a message queue.

Parameters

HAB hab (input)

Anchor block of calling thread (from WinInitialize or WinQueryAnchorBlock).

LONG maxMsg (input)

The number of messages the queue can hold. Pass 0 for system default.

Returns

HMQ hmq

Handle to the newly created message queue. NULLHANDLE is returned if there was an error. WinGetLastError will return one of:

0x100A PMERR_RESOURCE_NOT_FOUND

The specified resource identity could not be found.

0x1011 PMERR_HEAP_OUT_OF_MEMORY

An attempt to increase the size of the heap failed.

0x1012 PMERR_HEAP_MAX_SIZE_REACHED

The heap has reached its maximum size (64KB), and cannot be increased.

0x1018 PMERR_QUEUE_TOO_LARGE

An attempt to create a message queue has failed because the value specified for the size of the message queue is too large.

0x1051 PMERR_NOT_IN_A_PM_SESSION

An attempt was made to access function that is only available from PM programs from a non-PM session.

0x1052 PMERR_MSG_QUEUE_ALREADY_EXISTS

An attempt to create a message queue for a thread failed because a message queue already exists for the calling thread.

Define (C/C++)

#define INCL_WINMESSAGEMGR
#include <os2.h>

Example Code

#define INCL_WINMESSAGEMGR 
#include <os2.h> 

HAB hab; 
ULONG flOptions = 0L; 
HMQ hmq; 

hab=WinInitialize(flOptions); 
hmq=WinCreateMsgQueue(hab, 0L); 

if (hmq) {
          : 
         }

Related Functions

• WinDestroyMsgQueue
• WinPostMessage
• WinSendMessage